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[xen] Skip probing of any unsupported device types
Xen 4.4 includes the device "device/suspend/event-channel" which does
not have a "backend" key.  This currently causes the entire XenBus
device tree probe to fail.

Fix by skipping probe attempts for device types for which there is no
iPXE driver.

Debugged-by: Eytan Heidingsfeld <eytanh@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
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mcb30 committed Dec 28, 2017
1 parent aeffcce commit e4461f6
Showing 1 changed file with 21 additions and 18 deletions.
39 changes: 21 additions & 18 deletions src/interface/xen/xenbus.c
Expand Up @@ -206,13 +206,14 @@ static struct xen_driver * xenbus_find_driver ( const char *type ) {
*
* @v xen Xen hypervisor
* @v parent Parent device
* @v type Device type
* @v instance Device instance
* @v driver Device driver
* @ret rc Return status code
*/
static int xenbus_probe_device ( struct xen_hypervisor *xen,
struct device *parent, const char *type,
const char *instance ) {
struct device *parent, const char *instance,
struct xen_driver *driver ) {
const char *type = driver->type;
struct xen_device *xendev;
size_t key_len;
int rc;
Expand All @@ -234,6 +235,10 @@ static int xenbus_probe_device ( struct xen_hypervisor *xen,
xendev->xen = xen;
xendev->key = ( ( void * ) ( xendev + 1 ) );
snprintf ( xendev->key, key_len, "device/%s/%s", type, instance );
xendev->driver = driver;
xendev->dev.driver_name = driver->name;
DBGC ( xendev, "XENBUS %s has driver \"%s\"\n", xendev->key,
xendev->driver->name );

/* Read backend key */
if ( ( rc = xenstore_read ( xen, &xendev->backend, xendev->key,
Expand All @@ -253,18 +258,6 @@ static int xenbus_probe_device ( struct xen_hypervisor *xen,
DBGC ( xendev, "XENBUS %s backend=\"%s\" in domain %ld\n",
xendev->key, xendev->backend, xendev->backend_id );

/* Look for a driver */
xendev->driver = xenbus_find_driver ( type );
if ( ! xendev->driver ) {
DBGC ( xendev, "XENBUS %s has no driver\n", xendev->key );
/* Not a fatal error */
rc = 0;
goto err_no_driver;
}
xendev->dev.driver_name = xendev->driver->name;
DBGC ( xendev, "XENBUS %s has driver \"%s\"\n", xendev->key,
xendev->driver->name );

/* Probe driver */
if ( ( rc = xendev->driver->probe ( xendev ) ) != 0 ) {
DBGC ( xendev, "XENBUS could not probe %s: %s\n",
Expand All @@ -276,7 +269,6 @@ static int xenbus_probe_device ( struct xen_hypervisor *xen,

xendev->driver->remove ( xendev );
err_probe:
err_no_driver:
err_read_backend_id:
free ( xendev->backend );
err_read_backend:
Expand Down Expand Up @@ -310,11 +302,21 @@ static void xenbus_remove_device ( struct xen_device *xendev ) {
*/
static int xenbus_probe_type ( struct xen_hypervisor *xen,
struct device *parent, const char *type ) {
struct xen_driver *driver;
char *children;
char *child;
size_t len;
int rc;

/* Look for a driver */
driver = xenbus_find_driver ( type );
if ( ! driver ) {
DBGC ( xen, "XENBUS has no driver for \"%s\" devices\n", type );
/* Not a fatal error */
rc = 0;
goto err_no_driver;
}

/* Get children of this key */
if ( ( rc = xenstore_directory ( xen, &children, &len, "device",
type, NULL ) ) != 0 ) {
Expand All @@ -326,8 +328,8 @@ static int xenbus_probe_type ( struct xen_hypervisor *xen,
/* Probe each child */
for ( child = children ; child < ( children + len ) ;
child += ( strlen ( child ) + 1 /* NUL */ ) ) {
if ( ( rc = xenbus_probe_device ( xen, parent, type,
child ) ) != 0 )
if ( ( rc = xenbus_probe_device ( xen, parent, child,
driver ) ) != 0 )
goto err_probe_device;
}

Expand All @@ -337,6 +339,7 @@ static int xenbus_probe_type ( struct xen_hypervisor *xen,
err_probe_device:
free ( children );
err_directory:
err_no_driver:
return rc;
}

Expand Down

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